S M I T H S O N I A N A N N A L S OF F L I G H T ~ N U M B E R 9 Japan's World War II Balloon Bomb Attacks on North America Robert C. Mikesh SMITHSONIAN INSTITUTION PRESS City of Washington 1973 S E R I A L P U B L I C A T I O N S O F T H E S M I T H S O N I A N I N S T I T U T I O N T h e emphasis upon publications as a means of diffusing knowledge was expressed by the first Secretary of the Smithsonian Inst i tut ion. I n his formal p lan for the Insti? tut ion, Joseph Henry ar t iculated a p rogram tha t included the following s ta tement : " I t is proposed to publish a series of reports, giving an account of the new discoveries in science, and of the changes m a d e from year to year in all branches of knowledge." This keynote of basic research has been adhered to over the years in the issuance of thousands of titles in serial publications under the Smithsonian imprint , com? mencing with Smithsonian Contributions to Knowledge in 1848 a n d cont inuing with the following active series: Smithsonian Annals of Flight Smithsonian Contributions to Anthropology Smithsonian Contributions to Astrophysics Smithsonian Contributions to Botany Smithsonian Contributions to the Earth Sciences Smithsonian Contributions to Paleobiology Smithsonian Contributions to Zoology Smithsonian Studies in History and Technology I n these series, the Inst i tut ion publishes original articles and monographs dealing with the research and collections of its several museums and offices and of profes? sional colleagues at other institutions of learning. These papers repor t newly acquired facts, synoptic interpretat ions of data , or original theory in specialized fields. These publications are distr ibuted by mail ing lists to libraries, laboratories, and other in? terested institutions and specialists th roughout the world. Individual copies m a y be obtained from the Smithsonian Inst i tut ion Press as long as stocks are available. S. D I L L O N R I P L E Y Secretary Smithsonian Inst i tut ion Library of Congress Cataloging in Publication Data Mikesh, Robert C. Japan's World War II balloon bomb attacks on North America (Smithsonian annals of flight, no. 9) Bibliography: p. 1. World War, 1939-1945-Aerial operations, Japan. 2. Balloons. I. Title. II. Series. TL515.S5no. 9 [D792.J31 613.13'08s [940.54'49'52] 72-8325 For sale by the Superintendent of Documents U.S. Government Printing Office, Washington, D.C. 20402 Price $1.50 domestic postpaid or $1.25 GPO Bookstore Stock Number 4705-0009 Contents Page Foreword iv Acknowledgments v Introduction 1 Origin and Development 2 Transpacific Balloon 7 American Reaction 25 United States Military Countermeasures 28 Propaganda 37 Conclusion 38 Appendixes Detailed Description of A-Type Paper Balloon 40 B-Type Rubberized-silk Balloon 54 Hopper-Type Flight-control Apparatus 57 Payload Ordnance 58 Balloon Production 61 Inflating and Launching 63 Degree of Development 66 War Casualties on United States Soil 67 Otlier American Observations 69 Chronology of Balloon-bomb Incidents 69 Epilogue 82 Bibliography 83 Index 84 ui Foreword Mr. Mikesh has compiled the most complete account ever published on one of the most bizarre and obscure chapters in modem warfare. Never before had the United States received attacks launched directiy from an enemy shore. Never before had the American public been more in the dark about the nature of an attack, due to tight security measures. Although the damage caused by these balloons was slight, their psychological impact was real, and history should not overlook their use. Mr. Mikesh became an authority on this subject through personal interest while serving in the United States Air Force. He studied this subject in detail while stationed for a number of years in Japan and supplemented these findings with our own military records. Now a retired major, Mr. Mikesh has written authoritatively on the subject in a variety of publications, and this Annals of Flight represents the culmination of years of fastidious research on a fascinating subject. Michael Collins, Director National Air and Space Museum IV Acknowledgements My first note of thanks must go to a close family friend, Justis Webb, who sparked my interest in this subject in 1945. He had been an Air Force pilot flying C-47s on forest-fire patrols relating to the defense against the ballon bombs and gave me the first hint that such a weapon existed. Little was said about the balloons even after the war, but my curiosity continued to grow. In 1960, while researching another subject at the Aerospace Studies Institute, Maxwell AFB, Alabama, I casually mentioned by interest in Japanese balloon bombs to Miss Marguerite K. Kennedy, Chief, Archives Branch. Through her kind assistance, she and her staff searched their files and discovered a vast amount of material on this subject. It was at this time that I decided to prepare a definitive study about the Japanese balloon bombs, since little information other than brief accounts had ever been published. After ten years of collecting, researching, and interviewing many that were associated with the balloon bomb, I feel satisfied that as much relevant material as possible has been located for incorporation into this document. This could not have been possible had it not been for the help of a great many people. During my final four-year period in Japan, I was able to meet and discuss with many of those having firsthand knowledge of the balloon program. Among these were former Major Teiji Takada, engineer for the balloon project, who provided invaluable material and insight from his personal observations. For this, I am grateful. My thanks to former Colonel Susumu Nishuira, now Chief, Japan War History, Defense Agency, Ichigaya, Tokyo, for locating and making available to me the many Japanese documents on this military operation. I frequently think of the many laborious hours spent by my good friends, Mr. Tosuke (Jack) Magara, and Mr. Shorzoe Abe in providing the translations needed to make these documents meaningful to me. Mr. Mannoske Toda, publisher of Koku Fan, made his material on balloon bombs available for this study. Mr. Eiichiro Sekigawa was most generous as a close personal advisor and in providing many opportunities for acquiring this material in Japan through his affiliations in the aviation-writing and publishing field. Mr. Yoshiji (Eddie) Osawa was a great inspiration as a friend, having had firsthand experience as a boy in the hand manufacture of the balloons, and in relating his wartime experiences. Mr. James A. Winker, vice president of Raven Industries, Inc., provided a large amount of material. Through his company's association in the manufacture of balloons, material had been acquired about Japan's balloons and this file was made available to me. This provided many heretofore missing details for which I am very grateful. Colonel C.V. Glines, USAF (Ret.) gave continuing encouragement in seeing this project to reality due to his interest in the subject, and was most helpful in some of its preparation. Dr. Clarence S. Ross, formerly with the United States Geological Survey had been the mineralogist that evaluated the sand carried as ballast by the balloons. During our interview, he disclosed a great deal of information never before recorded on this subject which adds greatly to this study. When Mr. Frank Lara, public relations manager of die Weyerhaeuser Company, in Klamath Falls, Oregon, learned of this documentation project, he offered eager assistance with photographs and accounts surrounding die six casualties of the balloon bomb that occurred in the company's lumbering area. Meteorologists James F. Andrews and Philip F Clapp of the National Weather Service, Suitland, Maryland, were very helpful in their technical assistance relating to information about the upper air currents that carried the balloons across the Pacific. The help and encouragement of my colleagues at the National Air and Space Museum cannot go without special mention. Namely, these are Messrs. Louis S. Casey, Robert B. Meyer Jr., C. Glen Sweeting; and Louise Heskett of the Smithsonian Institution Press, who edited this manuscript. Mr. Roger Pineau, a former NASM colleague, has given unstintingly of his knowledge of Japanese history, language, and lore. His counsel and translations have been invaluable. The cover art work, which adds a touch of Japanese flavor to this study, was expertly done by Mrs. Keiko Hiratsuka Moore and is most appreciated. To all these people, and to any who may have been inadvertently overlooked I give my sincere thanks. Robert C. Mikesh 15 June 1972 Introduction The strategy of large-scale modern warfare, which leans very heavily upon the Intercontinental Ballistic Missile, may well have been touched off by die epic attack of the Doolittie Raiders against Tokyo in April 1942. Ironically, this mission also sparked the invention of the world's first intercontinental weapon. The concept of balloon bombs might have changed the course of the war in favor of the Japanese had it been pursued with more vigor and tenacity. The "Doolittie Raid" during World War II was planned against Japan to "cause confusion and impede production." The Americans knew that the bomb loads of these sixteen B-25 Mitchell bombers could not do enough physical damage to invoke any permanent delay of the war. But there were high hopes that the appearance of American planes over the Japanese home islands would be such a psychological blow tiiat the enemy might change their strategy of conquest to the benefit of the Allies. Doolittle had no way of knowing then, but the bold raid he led hastened the end of the war by encouraging the Japanese to engage the Americans at Midway and lose disastrously. In a desperate attempt to find a means of reprisal, the Japanese conceived a method to strike directly at the American continent. Their plan was simple; launch balloons with incendiary and anti? personnel bombs attached, let them travel across the Pacific with the prevailing winds, and drop on American cities, forests, and farmlands. It took over two years to design the balloons, bombs, and automatic dropping mechanism. Japanese scientists, spurred on by the fury of the militarists and the need for a return gesture which would regain them the "face" they believed they had lost in die eyes of die world, worked day and night to solve the technical problems. Finally, on 3 November. 1944, the first of more than nine thousand bomb-bearing balloons was released. It is estimated that nearly one thousand of the death-dealing balloons must have reached die North American continent. They were found over an area from Attu in the Aleutians, as far east as Michigan, and reaching southward to Mexico. They took die lives of six Americans and caused otiier damage, but their potential for destruction and fires was awesome. Even more important, if die extent of this remote kind of bombing had been known generally, the shock to American morale might have been worse than any potential material damage. Historians have tended to make fight of this use of man's oldest air vehicle, seemingly a pathetic last-ditch effort to retaliate against the United States. It was, however, a significant development in military concept, and it preceded today's intercontinental ballistic missiles launched from land or submarines. Had this balloon weapon been further exploited by using germ or gas bombs, the results could have been disastrous to the American people. Figure 1. The large Japanese paper bombing balloon in the rear of the exhibit hall in the Smithsonian Institution's Arts and Industries Building in 1972. This one was recovered at Echo, Oregon, on 13 March 1945 after making the Pacific crossing. (72-2993) 1 Origin and Development The Unexpected From widespread reports during 1944-1945, along with paper and metal fragments, United States military authorities began piecing together a fantastic story. The following are four isolated but typical incidents that led the military to become concerned. A father and son on an early morning fishing trip were just settling down when they observed a parachute or balloon-like object drift silently by and over Hie nearby hill. Moments later an explosion echoed through die valley leaving only a small trace of smoke coming from the direction in which the object had disappeared. By the time the two reached the area of the incident, fragments of paper were the only thing unusual in the silence of the north woods. The attention of two farmers at work in their field was diverted to a sudden explosion in a nearby field and an eruption of a cloud of yellow smoke. They moved cautiously to the scene, only to find a small hole in the ground witii metal fragments nearby. There was no evidence as to how this mysterious object was delivered. A mother tucking her sleeping child in for the night was shocked by a sudden flash of light through Hie window followed instantly by the sharp crack of an explosion in the silent darkness. Ranchers coming over the top of a hill near where they had camped the night before, discovered a partially inflated balloon entangled in the scrub brush. It had no bombs, but somewhere along its journey it had discharged its lethal cargo. A Japanese offensive had been launched using balloon-borne incendiaries and anti-personnel bombs carried by wind currents to the American continent. World War II air raids by enemy planes usually allowed ample warning for people to take cover, but this new threat against a nation that had never experienced an air offensive was being launched in silence without any form of warning by an air vehicle dating back to 1783. Figure 2. United States military and government officials inspect a Japanese balloon near Bums, Oregon, where it was discovered on 23 February 1945 (USAF 30776AC). The threat of an unheralded explosion with attendant death and destruction could panic the nation. There was no way of knowing the possible extent or duration of balloon launchings. In the dry season, widespread scattering of incendiary bombs could literally burn out the vast forests of the Pacific Coast. This was Japan's intended purpose along with the associated psycho? logical effect upon the American people. Then, there was the possibility of using balloons to spread germ warfare?a far greater menace.1 The threat to the nation was more frightening than the military or other govern? ment agencies dared reveal to the public, and so the situation was played down as much as possible. For Hie Japanese, this was not a simple air operation. It took two years of testing and preparation before the first bomb-carrying balloon was launched from Japan. But mey drew upon a technology that dated back much further. Early Balloon Programs At the siege of Venice when no position could be found for siege guns, it was decided to use balloons for bombardments. This was during the Italian War of Independence, 1848-1849, when Austrian Lieutenant Uchatius undertook the technical development of such a means of attack. Hot air balloons of thin paper were used. These balloons could carry bombs weighing thirty- three pounds for a half hour, and were dropped by means of a time fuse. The point of departure of the balloons was determined by the direction of the wind. No great material damage was done to the enemy, though one of the charges burst in St. Mark's Square. An unexpected shift of the wind drove some of the balloons back to the besiegers and their use was abandoned. The Japanese idea of a balloon bomb originated in 1933, when Lieutenant General Reikichi Tada, of the Japanese Military Scientific Laboratory, was assigned to the head the "Proposed Airborne Carrier Research and Development Program" which was to investigate and develop new war weapons. Several revolutionary weapons were already under consideration. The "I-Go- Weapon" was a small wire-controlled, manless tank which could attack enemy pillboxes and wire entangle? ments. The "Ro-Go-Weapon" was a project to develop a rocket propellant. Still another was a "death-ray" weapon which could kill enemy soldiers at close range with a charge of electricity. Though possible, the Japanese did not consider this aspect. Figure 3. Japanese paper bombing balloon (A 37180C). Of all the items under consideration in this series, the "Fu-Go-Weapon" seemed to offer the most promise. The idea was based on small, four-meter-diameter (13.1 feet), constant-altitude balloons capable of carrying explosives. The wind was to carry the balloons approximately seventy miles to enemy positions, where the bomb load would be released by a time fuse. It was hoped that the results would approximate in range and accuracy those of the heavy guns used by the Germans against Paris in World War I. This project appears to have been stopped in 1935 and never completed. Figure 4. A faulty ballast-dropping mechanism caused this balloon to land, without dropping its bombs, near Tremonton, Utah, on 23 February 1945. Little damage was caused to the envelope. An excursion into the Japanese language is warranted here to ensure an understanding of weapon nomen? clature. The term "Go" in this sense, is the equivalent of "Number." In the case of the "I-Go-Weapon," "I" (pronounced "EE") is the first character of the Japanese I, Ro, Ha syllabary. "Ro-Go-Weapon" could be properly translated to "Weapon No. B" or the second in this series. "Fu-Go" is the thirty-second character of the syllabary. These weapons are exotic by nature to be sure, but considering the time of their development, it is Figure 5. Americans were quick to inflate a recovered Japanese balloon for inspection of all components. This balloon was retrieved intact near Alturas, California, on 10 January 1945. (U.S. Army photograph, SC-226135) unlikely tiiat they were preceded by thirty-one advanced-weapon ideas. "Fu" happens also to be the first character in "Fusen," meaning "Balloon," and this probably explains why this weapon was termed "Fu- Go." Although conceived in the mid-1930s, ten years before its actual use, the idea of the balloon weapon system was never totally shelved. Limited research continued with the idea of using it to scatter propaganda leaflets in enemy territory, taking advantage of lower altitude winds. Balloons large enough to silently carry foot soldiers into enemy lines at night was also con? sidered. Thus, the element of surprise as obtained with the present-day paratrooper would be realized. With the onset of World War II, reorganization of army units placed the balloon-weapon research under the 9th Military Technical Research Institute,2 and the former Army Scientific Laboratory was discontinued. The degree of priority given to the "Balloon Bomb" Commonly called Noborito Research Institute, located where the Odawara Express Line crosses the Tama River on the southwest side of Tokyo. Flight testing eventually moved to Ichinomiya on the Chiba Peninsula, to later become one of the operational launch sites for the balloon offensive. project cannot actually be determined. Its importance was enhanced, however, by the Doolittie Raid on 18 April 1942, along with other methods or reprisal against the American continent. As the threat of air attacks against Japan became a continuing reality, with the American continent yet untouched, revengeful attack methods gained in importance. Other considerations included one-way bombing attacks by long-range, land-based bombers. There were, however, no suitable airfields within practical range of the United States. Japan kept trying until the end of the war to develop a bomber capable of non-stop flight from Japan to the United States, one way if necessary. An interim measure of launching small, bomb-carrying airplanes from submarines was studied and one attack was made by one Yokosuka E14Y1 aircraft (Allied Code name "Glen"), the night of 9 September 1942, starting small forest fires near Mt. Emily, Oregon. Improved planes and submarines were developed, but there was no promise forthcoming of any appreciable number of such attacks, and primary efforts were diverted to other projects. The research project of balloon weapons was continued in an effort to bomb the American continent. In March 1943, a six-meter (19.6 feet) balloon with a desired range of 3,000 kilometers (1,863 miles) was developed which flew 1,000 kilometers (621 miles) between the west and east coasts of Japan. It was found that this model could stay in the air for more than thirty hours at an altitude of 8 kilometers (26,247 feet). This type of balloon was further developed so that all components could be loaded on board submarines through their restrictive hatches. The balloon was to be inflated on the deck of the submarine, then attached to it was an automatic altitude-control device, a time mechanism for releasing a bomb, and one 5-kilogram incendiary bomb. The balloon was to be launched from the submarine on the surface at night approximately 620 miles from the United States giving it a flight time of about ten hours. Success probability for flight was quite good provided a flight was confined to daylight or night time, but not to both. Gas expansion and contraction caused by day-night temperature change would create problems with longer flight times. So much importance was attached to this effort, that it was made a joint army-navy research project. The navy would equip two submarines3 at the Kure Naval Base with balloon launching facilities, while the army would concentrate on balloon development and ordnance to be dropped from them. Two hundred balloons were assembled for this operation. Plans were nearing completion when the submarines being modified for this mission were recalled for the Guadalcanal operation, resulting in the discontinuance of this project in August 1943. The acute war situation dictated that every available submarine was needed to transport weapons and food to the starving Japanese troops in the islands. As the noose of Allied might drew tighter around the Japanese, the necessity for some way to carry the fight to the enemy's shores became more urgent. The develop? ment of longer range balloons launched from Japanese soil seemed to be a logical answer. Submarines 1-34 and 1-35 were so equipped. Transpacific Balloon Meteorology The idea of "inter-continental free-flight balloons" was feasible. There was a continuity of wind patterns over Japan and over the American continent. The 9th Military Technical Research Institute sought the advice of the Central Meteorological Observatory in Tokyo, where meteorologist H. Arakawa was asked about the feasibility of using these wind currents. He was also asked the following questions. At what altitude should the selection be for the balloon bombs to travel? What seasons are most favorable to the project? How many days would it take for balloons released from Japan to reach the central zone of the United States? What would be the diffusion of the constant-level balloons over North America? Fairly accurate data was available to Mr. Arakawa concerning winds from the Asian continent that crossed over Japan, but winds over the Pacific were relatively uncharted. The phenomenon of local wind speeds of 200 to 300 kilometers per hour (120 to 185 miles per hour) at certain latitudes and at higher altitudes of around 12 kilometers (39,370 feet) in the winter months were being studied and needed further research. Little was known of air currents above 13.5 kilometers (44,291 feet). Between 1942 and 1944, facts were collected and studied from the seven Japanese radiosonde stations at Sendai, Niigata, Wajima, Yonago, Fukuoka, Shio-no- Misaka, and Oshima (see Figure 6). From these records of the upper air in scattered regions of Japan, sup? plemented by surface weather observations from ships and islands over the Pacific Ocean, Arakawa was able to develope logical wind-flow patterns extending across the Pacific. These "rivers of fast moving air"?later called "jet streams"?which had been studied in Japan did not become a major matter of American interest until high-level, B-29 bombing raids against Japan were well under way in 1944. Beginning in October, the jet stream is quite strong over or south of Japan above the 9.1-kilometer (30,000-foot) level, and it attains maximum velocity from November through March. Use of this jet stream increased the chances of success in the employment of this balloon weapon. The method used to estimate the upper wind pattern near 12 kilometers, very briefly, was to assume that the decrease of temperature with altitude over the Pacific was given. Then, using surface weather observations, it was possible to calculate the pressure field at this altitude. The horizontal gradient of pressure, together with the latitude, then gives the geostrophic wind speed. From these calculations, the flying course of the balloon, its speed, and its diffusion were analogized, and optimum launch locations were determined. It was noted that the upper air stream varied considerably in curve as it reached the American continent. The air stream in the American continent area would generally flow to the southward, while this could vary as the balloon would descend as it neared its destination. The time required for a balloon to transit the Pacific Ocean was estimated to be from tiiirty to one hundred hours with an average time of sixty hours. To substantiate these findings and determine the feasability of spanning the Pacific, some two hundred paper balloons4 were launched during the winter of 1943-1944. These meteorological tests were a joint effort along with engineers whose task was to develop the transpacific balloon. Attached to each experimental balloon was radiosonde equipment to collect and transmit upper air information to stations in Japan. None of the balloons reached the United States nor was that the intention. From the information derived and further calculations, answers to the meteorological ques? tions were obtained and Japanese engineers?encouraged by the probability of success?proceeded with enthu? siasm. Engineering Obstacles The main concern that faced engineers for the "Fu-Go Weapon" was to develop a method of keeping the balloon flying at a fairly high altitude for the fifty to seventy hours it would take to cover the 6,200 miles of ocean. If the balloons were launched in the daytime, These were the balloons that had been placed in storage for some future use after the submarine-launched, balloon operation was terminated. SENDAI OSHIMA SHIO-NO-MISAKA Figure 6. Radiosonde plotting-station locations in Japan used for upper wind study in 1945. continuous sun radiation in clear skies at the upper altitudes would cause the gas temperature to rise from an average of 0?C. to more than 30?C. in the afternoon on the side of the balloon facing the sun. This would expand the balloons to the bursting point. At night, the reverse would be true since the temperature is usually -50?C, and at 33,000 feet atmospheric pressure is approximately one-fourth the pressure at sea level. The balloon would thus lose excessive altitude as it lost buoyancy. By using the experience gained from the six-meter- diameter balloons, the problem was solved by the installation of a gas discharge valve at the base of the balloon, and attaching an ingenious automatic system for dropping ballast. The size of the balloon had to be large enough to support the increased load of ballast and the metering valve, which together controlled the balloon altitude. To obtain this added endurance for increased range, a ten-meter-diameter (32.8 foot) bal? loon was determined as optimum for this requirement. The buoyancy of the ten-meter balloon was about five times that of the six-meter balloon. The balloons, usually made of three and four layers of tissue paper cemented together to form a gas-proof sphere, were inflated with hydrogen to a capacity near 19,000 cubic feet. When filled, they had a lifting capacity of 1,000 pounds at sea level and about 300 pounds at 30,000 feet. The balloon envelope was encircled by a scalloped cloth band to which numerous shroud lines were attached, and these were tied together below in two large knots. From these knots, the bombs and ingenious ballast release mechanism were suspended. The altitude-control mechanism was developed under the supervision of Technical Major Otsuki of the Noborito Research Institute. This device consisted of a cast-aluminum wheel from which bags of sand were hung. By means of aneroids and a small battery, a release fuse attached to two sandbags was ignited whenever the balloon reached a preset minimum altitude. The balloon then would rise again to approximately 38,000 feet, and be carried along by the higher winds. It would sink to the minimum desired altitude?around 30,000 feet?as the gas slowly escaped or was cooled. Two more sandbags were then dropped, as the process was repeated. When all thirty-two sandbags were expended, the balloon would discharge its load of bombs and destroy itself by a small demolition charge. The number of cycles required was calculated, based upon forecasted wind speeds, and appropriate settings were made to position the balloon over the American continent for bomb release. The next engineering problem was unusual tempera? tures and pressures that the balloon equipment would encounter. All Japanese army equipment was designed to operate to extremes of-30?C; however, at-50?C. at the 260-millibar pressure level, rubber components and springs lost their elasticity. Also electrical batteries were greatly reduced in power output, and ballast-dropping explosives lost reliability because of the low pressure. Therefore, considerable research was directed toward high-altitude explosives, antifreeze batteries, and the use of solar heat and other insulation methods. As these tests were being made between May and August 1944, nearly all dry ice in Tokyo?for testing cold resistance of components?was diverted to this project. It was a common practice for scientists working on this program to personally check daily on the status of the ever-dwindling supply of dry ice. Tests conducted to determine direction and altitude of the balloon, skin and gas temperatures, gas pressure, ballast dropping, altitudes gained by the balloon, and the functioning of the gas-relief valve with relation to air-pressure expansion were all monitored by radio. For this reporting purpose, many types of radiosonde equip? ment had to be developed. Probably the greatest difficulty for the Japanese was developing a radiosonde that could operate consistently under varying stratospheric conditions. The respon? sibility for development of such a system went to the Japanese 5th Army Technical Research Institute. The primary purpose of the radio equipment would be to report the balloon's flying course, its altitude, and to measure the balloon's inside pressure. In addition, it would also provide data on the balloon's descending and ascending flight. This would give an added indication of when the ballast was being dropped. The first tests were conducted from Chiba Prefecture, east of Tokyo. At the time, there was no radiosonde known which could operate for the desired length of time in strato? spheric conditions. Success of the balloon-development program depended upon this radio-reporting equipment. The development of a power source of adequate durability and the selection of proper frequencies caused the-most trouble. In order to check the functioning of radio equipment during these experimental flights, various models of the radiosonde apparatus were developed and suspended from balloons. Many agencies became involved in the development of radiosonde equipment. Included was the Army Weather Bureau that assigned their most experienced member, Engineer Yuasa Matsumoto, who developed no less than ten experimental radiosonde transmitters for this effort. After considerable research, an adequate radio set was finally developed. Attached to a balloon and released in free flight, it operated for eighty continuous hours, relaying back the valuable flight information. The radio fell silent when the balloon reached a point at longitude 130? west; however, engineers were exuberant with the results. They concluded that a balloon could cross the Pacific in three days during the winter period from November to March. The radiosonde equipment developed for observing the balloon's flight course produced a continuous wave, moderated by a multivibrator. This piece of equipment had a power output of two watts with an alternating A and B frequency which worked on an alternating cycle. ftA" frequency would operate ten minutes and rest ten minutes. While "A" was resting, "B" would operate and vice versa. Navy Balloon Paralleling the army's paper-balloon program but with a later start, the Imperial Japanese Navy also began a study of balloon bombs to utilize a skin of rubberized silk. This became known as the "Internal Pressure Type" balloon. Both balloon designs were of similar size, but the payload of the silk balloon was not as great due to the greater weight of the envelope. Instead of controlling altitude by the release of ballast and venting excess gas pressure, as was the case with the paper balloon, the navy's version was sealed after filling, being designed to keep its volume constant, yet strong enough to tolerate pressure changes with temperature and altitude. Flight altitude was relatively stable, making this one of the more favorable features of this balloon concept. Consistent flight altitude made for Figure 7. Imperial Japanese Navy's balloon development consisted of a rubberized-silk envelope. Due to the weight, its payload was much less than the paper balloon developed by the army. (U.S. Air Force photograph, 30770). better plotting of weather data and tracking the balloon flight path; however, readings of gas pressure became their highest by 3:00 P.M. daily during flight and many balloons failed at this point in time. A safety valve was then installed on subsequent balloons that would vent hydrogen at 50 millimeters Hg (by mercury barometer)5 which resolved the problem. This retained sufficient pressure, causing little effect upon buoyancy. A light? weight and simple ballast-dropping mechanism was also employed. The internal pressure-type balloon for the navy was originated by Rear Admiral Naneko Kichisaboro, head of the Sagami Naval Arsenal. Captain Ogawa, head of the United States technical evaluation shows this figure to be 35 millimeters of mercury. arsenal's research and development, and Professor Tatsusuke Nakamura, of the Imperial University at Nagoya, collaborated in the design study. In the spring of 1944, all army and navy balloon research was again consolidated. The navy's balloon project, supervised by Technical Lieutenant Commander Kiyoshi Tanaka, was moved to, and became part of, the Army's 9th Military Technical Research Institute. The continued development of this balloon was assigned by Major General Sueyoshi Kusaba, the head of the project, to Technical Major Takada with Commander Tanaka of the navy to assist him. At this time, the army assigned "B-Type" as the designation for navy-developed balloons, while continuing with the term "A-Type" for the paper balloons. 10 Despite continued research in this balloon concept, the results were disappointing. The buoyancy of the B-Type balloon was nearly zero at the ground, causing ascent to be quite slow. While the A-Type balloon reached the 10,000 meter altitude within forty minutes, it took the B-Type from two, to two and one-half hours to reach the fast-moving jet stream at that altitude. This also made launching rather difficult when there was any wind, for the balloon and its payload would be damaged as it skipped over the ground before rising. Usually, from two to three B-Type balloons were released daily from Ichinomiya carrying radiosonde gear for experimentation and tracking. Finally, it was concluded that mass production of this balloon was impractical because of the heavy drain of manufacturing resources and materials otherwise used for explosives. One engineer on the project stated: "There was no other reason than this lack of material for this more durable and reliable balloon skin, that the noncritical paper- material balloon was placed in service." Consequently, production was limited to three hundred of the B-Type balloons before this navy-originated concept was abandoned. Traditionally, neither Japanese military service wished to be subservient to the other or, for that matter, willingly share in the other's project. Therefore, the Japanese navy continued with balloon research under a new concept which consisted of balloons capable of carrying a crew to effect some flight control. The bombs were attached individually to small balloons and used as ballast weight for release to drift independently to the targets, and thus achieve stabilization in altitude of the main balloon. A model test was conducted at the Fujikura Industries Company in Tokyo, but never went beyond the testing stage before the war ended. Other exotic ideas were brought up, but never materialized. under the control of General Mimura, to be assisted by the Itabashi Research Institute of the Army Arsenal, as well as scientists outside the army. This suggestion was approved, and a program for accelerated research for components of balloon bombs was prepared. The first meeting of scientists and technicians concerned was held at the Weapon Administration Bureau at Wakamatsu-cho, Ushigome-ku, Tokyo. The date of this event is not recorded, but it is presumed to have been held in May 1944. Major General Sueyoshi Kusaba, who had been the key figure in the develop? ment of the Fu-Go Weapon from the early beginning led the study group. He briefly related the current develop? ment status of the program, and then took four hours to deliberate on the problems yet to be solved. Each research institute was asked to assist in the areas of their expertise. Shortly following this conference, each research institute received approval for study under the authority of the commander of the Weapon Administration Bureau for the Fu-Go Weapon. A two-million-yen budget was allotted to the Noborito Research Institute for the project. The research group headed by General Kusaba took charge of flight experiment, coordinated and conducted the "Fu-Go Research Project" from each of the other institutes, and thus became the focal point of the entire project. Consultants on general affairs were Dr. Hidetsugu Yagi, Dr. Sakuhei Fugjwhara of the Central Meteoro? logical Observatory, and Dr. Tatsujiro Sasaki of the Aeronautical Research Institute. Dr. Masaichi Majima of the Tokyo Imperial University acted as chairman for the project. Manufacture Accelerated Development With test flights showing positive results, the research group concluded that "the attack against the North American continent with balloons flown from the Japanese homeland was not impractical." The group added to this conclusion, however, that many problems still remained to be solved before the balloon operation could be successfully implemented. Lieutenant General Shinoda, director of the Noborito Research Institute, related the status of development to his superior, General Mimura, Commander of Weapon Administration Bureau, and suggested that for the timely solution of unsolved problems, cooperation of eight institutes would be necessary. These should be While experimentation continued in the early part of 1944, manufacturing facilities for balloon envelopes were being set up in seven different locations in the vicinity of Tokyo. By manufacturing the balloons in this general area, distance to the launch sights was reduced. This minimized creasing the envelope and other damage in shipping that could increase the possibility of gas leakage. Components for the release mechanism were made by several manufactures and shipped to the launch sites along the nearby coastline for final assembly. The factory operations were supervised by a Captain Nakamura and a civilian technician. Some of the industrial firms concerned and connected with the operation were the Mitsubishi Saishi (paper factory), the Nippon Kakokin Company, and the Kokuka Rubber Company. The panels were then sent to subcontractors 11 Figure 8. Japanese technicians struggle with an experimental balloon operation at the Sagami Arsenal in the spring of 1944. Figure 9. Surface wind was the greatest detriment while filling the balloons and releasing them for flight. 12 who assembled the envelopes into the finished products. The program called for 10,000 balloons to be mass produced in time for the approaching fall and winter winds of 1944-1945. Mr. Teiji Takada, a former technical major at the Noborito Research Institute, clearly defines the magnitude of such an undertaking. To cope with the requirement of 10,000 balloons, all materials were considered with reference to their critical resources compared to the research necessary for substitute materials. Ten thousand balloons would carry about 1,800 tons of articles, while the total weight of hydrogen cylinders to be prepared to fill these balloons equally amount to 1,200 tons. Visualizing that hundreds of slowly burning fuse cords, along with hundreds of thousands of electric detonators were required, we could fully perceive what the number 10,000 means. One of the earlier technical problems that had to be solved was to design an inexpensive gas-proof balloon bag of noncritical material that could be mass produced. After much experimentation, it was found that good results could be obtained from tissue paper made from fibers of the kozo bush, a member of the mulberry-tree family, but very similar to the American sumac.6 The paper was to be obtained from the hand- man ufactured-paper companies all over Japan; however, with these various sources, the standard of quality could not be controlled. The strength of the paper was dependent chiefly upon the fiber which had to be uniform, yet it was necessary to have it be very light. The size of the sheets also varied with each manufac? turer. Lieutenant Ito of the Noborito Institute made a technical breakthrough when he developed a mechanical method of processing the kozo fiber into paper. Not only could sheets of desired size be manufactured, but a mechanical method of laminating the layers was also developed. This was a revolutionary event in the age-old hand process of Japanese paper manufacturing. For gas-proofing the paper, many types of sealers were tested; one produced a wax paper and another, natural gum. Both were too heavy. An adhesive called konnyaku-nori, made from a type of Japanese potato,7 proved to be best for joining the seams. At a time when there was an acute food shortage in Japan, it was not unusual for laborers to be caught stealing the powdered In addition to kozo (Broussonetia Kazinoki), the matsumata (Edgewortia Papyrifera) tree was also used in the manufacture of Japanese paper for the balloons. Also commonly called arum root. konnyaku* that was used to make the paste sealant, as this was a very stable food substance. Coloring was added to the paste to let those engaged in the applica? tion know how evenly it was applied to ensure gas- proofing. After the paper?now laminated?was dry, it was inspected for possible flaws. This was done in a dimly fit room that was floored with frosted glass having electric fights placed beneath it. Sheets of raw paper placed individually upon the lighted floor became translucent with a bluish color caused by the adhesive. Areas of light color showed up as being insufficiently pasted, while even a hair on an inner layer from a pasting brush was quickly spotted. Defects were circled with chalk; and in an adjacent room, patches were applied over these areas. The raw, handmade, standard-weight paper made from the mulberry tree was fifteen grams per square meter. Strength was gained by laminating the three and four layers of paper alternately lengthwise and breadthwise. Next, the panels were softened by dipping them in a solution of soda ash, a water wash, and then a solution of glycerine. The glycerine wash was soon re? placed with calcium chloride and other softeners since munitions powder had a higher priority for the glycerine than the balloon project. After the panels were dried, the edges were trimmed and panels were pasted together on a spindle form, the upper part first, then the lower part. Each balloon consisted of 600 separate pieces of paper, all having to be glued together with no allowance for gas leakage. After the relief-valve neck was installed in the lower hemisphere, both hemispheres were joined together by an encircling scalloped band which was glued on. This band formed the suspension skirt to which the shrouds were attached. A large floor area was required for the shaping and final assembly room. All protrusions?not only on the floor but around the walls?were carefully wrapped with paper, to protect the balloon skin from damage. It was difficult to detect skin abrasions once the balloon was assembled. Girls that were malting the balloons were instructed not to wear hairpins, to have closely trimmed fingernails, to wear socks even in the midsummer heat, and to use gloves despite the fact that their work required manual dexterity. To test the balloons for possible leaks, buildings large enough to house the inflated thirty-three-foot-diameter envelopes were required. Large theaters and sumo wrestling halls were ideal, but more were needed and had to be built for the testing which added considerably to the cost of the balloons. Such buildings as the Nichigeki In later years, as war tensions eased, Japanese lightheartedly referred to the "Fu Go" as the "Konnyaku bakudan" ("Konnyaku bomb"). 13 3 Ml < ON (N .ft -SH3?3W JO SONVSnOHl 'sa3i3w JO soNvsnoHi NI 3an i i j . i v 14 Figure 12. Great numbers of Japanese high-school girls were used in the delicate work of pasting and stitching the balloon envelope. Music Hall and the Toho Theater in Tokyo, and Kokugi-Kan Wrestling Hall in the Tokyo borough of Asakusa were used. For the test, the balloon was filled with air blown into it at a pressure of 120 meters of water column, after which it was sealed. After twenty-four hours, it was checked for leakage. Those that were satisfactory were then coated with a protective lacquer. The earlier paper balloons were made in factories, but when the demand reached its peak, the factories processed the paper and made the majority of the panels. The panels were then sent to subcontractors who assembled the finished product. Figure 13. Large arenas and theaters were used for balloon production and inflation testing. One building was the Nichigeki Music Hall, a familiar modem-day landmark in downtown Tokyo. 15 Figure 14. A skyward view of an inflated balloon held captive by its shroud lines. The gas relief valve is shown at the base of the envelope. (A 37180F) Figure 15. The Japanese paper balloons were 32 feet in diameter and, when fully inflated, held about 19,000 cubic feet of hydrogen. (A 37180F) In numbers, school children were the greatest labor force on this project. During wartime, school hours were short in order that the remainder of their day could be devoted to the war effort. Thousands of Japanese had a part in making these balloons, but officially they were never told of their purpose. Even when word about their intended use would filter down, no one believed it. Two years of experimentation and some 9,000,000 yen (more than 2,000,000 prewar dollars) were spent on the manufacture of balloons. Still another source quotes the original price per balloon at 10,000 yen, roughly $2,300 at the prewar rate of exchange, but this cost was considerably reduced as production increased. It is difficult at this time to accurately determine from these figures what actual costs were involved. Balloon Launch Sites While the fabrication of the balloons was underway, the army formed a new operational unit called the Special Balloon Regiment, under the command of Colonel Inoue. Its responsibility was to prepare launch sites, establish direction-finding station locations, prepare for gas-production facilities, and train personnel in the launching of the balloons. Three general site locations were selected along the lower half of Honshu's eastern seaboard. These areas were chosen because of nearby rail lines and favorable terrain. Also, the coastal sites lessened the possibility of damaging Japanese property through flight mal? functions. Of the thousands of balloons released, only two returned to Japan. Both occurred on 13 March 1945, twenty fours after launching, but they fell in snow and caused no damage. The first landing was reported near Hakodate on Southern Hokkaido, while the second was located in Akita Prefecture. The northern regions of Japan were ruled out as launch sites because of the possibility that balloons might stray into Kamchatka, a Soviet Union territory, and cause an international incident. Balloon launch locations and their unit and functions that occupied them were as follows: Otsu, Ibaraki Prefecture Command Headquarters. First Battalion (composed of three squadrons). Total strength: 1,500. Weather Unit (in connection with the Army Weather Bureau). Ichinomiya, Chiba Prefecture Second Battalion (composed of three squadrons). Total strength: 700. Test Release Unit. Nakoso, Fukushima ftefecture Third Battalion (composed of two squadrons). Total strength: 600. Hydrogen-generation plants became the key to launch operations. The Nakoso and Ichinomiya sites depended upon the gas being transported in tanks from distant Kanto Plain companies, such as Showa Denko (a chemical and electric company still operating under this 16 IWANUMA (l D.F. STATION) NAKOSO (6 LAUNCH STATIONS) OTSU (O LAUNCH STATIONS) O H A R A ) ICHINOMIYA (e LAUNCH S T A T I O N S ) ( I D.F. STATION) Figure 16. Balloon launching sites and flight-following stations. name). The Otsu site, however, was capable of generating its own hydrogen from the beginning of the operation. Launching Operations To achieve the greatest effect from the balloons based upon weather forecasts, the following proposed launch schedule was worked into the plan, based on the possibility that 15,000 balloons would be available (actual balloon operations are shown for comparison). Date November 1944 December January 1945 February March April (early) Total To be launched 500* 3,500 4,5J)0 4,500 2,500 0 15,000 Approximate number launched 700 1,200 2,000 2,500 2,500 400 9,300 ?Anticipated difficulties with the new program accounted for this low figure. 17 Figure 17. Balloon launching complex at Otsu after the war. Note the shelter caves in the side of the hills and the sea in the background. (U.S. Army photograph, SC 284816) Figure 18. The United States Army's First Cavalry Division, on maneuvers in occupied Japan on 22 April 1947, discovered these former balloon launching sites at Otsu. (U.S. Army photograph, SC 283906-S) 18 * 9 ^ ? > ' ? . ? ? ' ? ! - . ''?} 82S S a R"' i 8sMs ft) % * 78 79 ? 80 o b b ? b b 05 J o ? o 1 ** * in fO o 3 o ' IS LA ND 1 s 2 ? . -* ; ? ? o *> o **? ? * ?*> I I I 2 S 2 . A N 0 S A 1 1 A N IS ,0' m Je ? H A W ?> ^ 7 oi |r~^ >7 j, (V V W ^ Ili ? o ? o ? b b o b 43 E o x> c o o .6 81 Epilogue While the bold experiment with the balloon bomb is now history, the dangers of the balloon bomb still may exist. Hundreds of these bombs were never found and may still be detonated with the slightest contact. On 1 January 1955, the Department of Defense released word that such a bomb, "still highly explosive and dangerous even after exposure . . . for nearly a decade," had been found in Alaska. This news release is further quoted in part: Flying low between Barter Island and Fort Yukon, Don Hulshizer, Chief Bush Pilot for Wien Alaska Airlines, Fairbanks, Alaska, spotted a dull white object on the ground near the Scheenjek River. He decreased altitude in an attempt at identification, but because of the rough terrain he was unable to distinguish the object clearly. Surmising that the find was either a parachute or part of a downed aircraft, Hulshizer contacted Air Intelligence officers at Ladd Air Force Base near Fairbanks, Alaska. Attempts by L-20 and SA-16 search craft to relocate the strange object at first proved unavailing due to the thick carpet and tundra-brush and undergrowth. Finally sighted and pinpointed, Air Force officers determined that the best chance for its recovery lay in a helicopter operation. The 74th Air Rescue Squadron at Ladd supplied a H-5 helicopter as well as a SA-16 aircraft to fly protective cover on the 230-mile trip. The helicopter was unable to land, but L t Harold L. Hale, of Pueblo, Colorado, an intel? ligence technician with the 504th Air Intelligence Squadron, dropped to the ground. He too thought it was a parachute but after discovering the "chute" was made of paper and that the gondola was most unusual, he was reasonably sure it was of Japanese origin. He stuffed the balloon under a tree so it- would not be reported again as an unidentified object, and loaded the remaining 120 pounds of the strange object into the hovering helicopter. The device was sent to Wright-Patterson AFB, for closer inspection, and it was discovered that the explosives were still quite potent even after the many years of exposure on the ground in the northwest woods. A brief examination of maps showing downed- balloon locations reveals that the more populated and traveled areas show the largest number discovered. It would be safe to assume that the same intensity would prevail over the adjacent wilderness and therefore hundreds of balloons and their bombs have yet to be discovered. Experts say there is no way of knowing how long these uncovered bombs will continue to be highly explosive. Hunters, hikers, and fishermen are especially warned to report the location of any bombs found to the nearest military installation without delay. It would be the surpreme irony if any more American lives were lost to the "Fu-Go Weapon" revenge bomb of a war the world wants to forget. 82 Bibliography Arakawa, H. Basic Principles of the Balloon Bomb. Mete? orological Research Institute, Tokyo, Japan, January 1956. 5 pp. "Balloon Bomb in Alaska." New York Herald-Tribune, 2 January 1945. "Balloons . . . But Japan Never Knew Outcome." New York Times, 29 May 1947. "Blast Kills 6." Herald and News (Klamath Falls, Oregon), 7 May 1945. "Bomb-Laden Balloons Fizzle." New York Times, 16 August 1945. Conley, Cornelius W. "The Great Japanese Balloon Offensive." Air University Review, February-March 1968, pp. 68-83. Davis, Jack. "Japanese History Relived." The Afterburner (Yokota Air Base, Japan), 18 October 1963. Groueff, Stephane. Manhattan Project: The Untold Story of the Making of the Atomic Bomb. Pp. 353-355. New York: Bantam Books, 1968. Hirata, Tatsu, [Paper-made ICBMs.] Koku Fan Magazine, September 1964, pp. 67-73. [In Japanese.] "Japanese Balloons." Chapter 10. Fourth Air Force Historical Study No. III-2, pp. 501-516. [n.d.] "Japanese Balloons Sighted-First Complete Story." Herald and News (Klamath Falls, Oregon), 17 August 1945. "Japanese Free Balloons." Army Service Forces, Hq. 4th Service Command, (10 July 1945), 14 pp. [Unpublished manu? script.] "Japanese Free Balloons." Western Defense Command Intel? ligence Study, No. 1 (10 February 1945). 55 pp. [Un? published manuscript.] "Japanese Free Balloons and Related Incidents." Military Intel? ligence Division, War Department. Reports 1 through 8. [Unpublished manuscript.] "Japanese Paper Balloon" Guggenheim Aeronautics Laboratory, Report for Western Sea Frontier (4 April 1945). 44 pp. [Un? published manuscript, n.d.] LaPaz, Lincoln. "Japan's Balloon Invasion of America." Colliers, 17 January 1953, pp. 9-11. McKay, H.W. "Japanese Paper Balloons." The Engineering Journal, September 1945, pp. 563-567. Mineralogy and Some of Its Applications, pp. 17-18. Cambridge, Mass.: Mineralogjcal Society of America, Harvard University [n.d.; pamphlet]. "9000 Balloon Bombs Against U.S." Washington Post, 16 January 1946. "Piccard Flies Japanese Paper Balloon." New York Times, 17 February 1947. "Raids by Japanese Balloons." New York Times, 9 February 1946. "A Report on Japanese Free Balloons." Coast Artillery Journal, March-April 1946. 4 pp. [A Report on the Research of the Bombing Balloon.] Ninth Military Laboratory, Weapon Administration Bureau, October 1945. [In Japanese.] Takada, Teiji. [Balloon Bomb, I.] Shizen, vol. 6, no. 1 (January 1951), pp. 24-33. [In Japanese.] . [Balloon Bomb, II.] Shizen, vol. 6, no. 2 (February 1951), pp. 44-54. [In Japanese.] [Balloon Bomb, III.] Shizen, vol. 6, no. 3 (March 1951), pp. 70-77. [In Japanese.] Weidner, George E. "Japanese Bombing Balloons." Technical and Technological Survey (United States Army), PB Report 28880, (2 January 1946). 32 pp. Wilbur, H.W. "Those Japanese Balloons." Readers Digest, vol. 57, no. 8 (August 1950), pp. 23-26. 83 Index Aeronautical Research Institute, 11 Air Fields, United States: Moffett Field, 34 Paine Field, 34, 35 (Figure 37) Quillayute Naval Auxiliary Air Field, 34, 35 (Figure 37) Santa Rosa Army Air Field, 29 Shelton Naval Auxiliary Air Field, 34, 35 (Figure 37) Walla Walla Army Air Field, 28, 29 Air force units, United States: Continental Air Force Headquarters, 36 Eleventh Air Force, 36 504th Air Intelligence Squadron, 82 Fourth Air Force, 28, 29, 32, 34 Airplanes, United States: B-25 (Mitchell bomber), 1 B-29 (Super fortress), 7, 23, 38 C-47, 29 E14Y1 ("Glen"), 6 F4U (Vought Corsair), 29, 31 F6F (Grumman Hellcat) 29, 31 L-5 (Stinson), 29 L-20 (De Havilland U-6 Beaver), 82 P-38 (Lockhead "Lightening"), 29, 30, 34 P-61 (Northrup "Black Widow"), 34 P-63 (Bell King Cobra), 28-30 Akayu,Japan, 69 Akita Prefecture, 16 Altitude control device, automatic, 45 Aneroid, 45, 46 Arakawa, H., 7 Army units, Japanese; Arsenal, 11 5th Army Technical Research Institute, 9 9th Military Research Institute, 5, 7, 10. See also Noborito Research Institute. Scientific Laboratory, 5 Special Balloon Regiment, 16, 24 Weather Bureau, 9, 16 Asakusa, Tokyo, 15 Ballast, 54 Balloons: interception of, 29 paper, Japanese manufacturers of, 62 rubberized-silk, Japanese manufacturers of, 62 ZMK barrage, 33 Battery, 50 (Figures 63-65), 54 Blowout plug, 47, 48 Camp Evans Signal Laboratory, 32, 33 Captive-balloon experiments, 32 Casualties, 67 Central Meteorological Observatory, Tokyo, 7,11 Chesapeake Bay Annex, 32, 33 Chiba Prefecture, 9 Demolition charge, 54 Direction finding, 17, 24. See also Flight-following. Domei News Agency, 37 Doolittle (James) Raiders, 1, 6, 38 Engen, Eddie, 67 Firefly Project, 29 Flash bomb, 43 Flight-control apparatus. See Hopper-Type. Flight-following, 17 (Figure 16) Fugiwhara, Dr. Sakuhei, 11 "Fu-Go-Weapon, 3, 7, 11, 13n, 21 Fujikura Industries Company, Tokyo, 11 Fukuoka, Japan. 7, 8 (Figure 6) Fuses, 43 Geological Survey, United States, 34, 35 Gifford, Jay, 67 Gordon, Senator Guy, 68 Guadalcanal operation, 6 Hakodate, Japan, 16 Hale, Lieutenant Harold L-, 82 Headlight tracer, 29 Hidano, Captain Monomichi, 69 Hopper-Type flight-control apparatus, 57 Hulshizer, Don, 82 Hydrogen, 8, 13, 16, 17,42,62 Ichinomiya, Japan, 5n, 11, 16, 17 (Figure 16), 20 (Figure 21), 24,69 "I-Go-Weapon," 3, 4 Imperial University, Nagoya, Japan, 10 Inoue, Colonel, 16 Itabashi Research Institute, 11 Ito, Lieutenant, 13 Iwahana, Japan, 61 Iwanuma, Japan, 17 (Figure 16), 24 Kamchatka, region, U.S.S.R., 16 Kamikaze, 21 Kichisaboro, Rear Admiral Naneko, 10 Kokugi-Kan Wrestling Hall, 15 Kokuha Rubber Company, 11 Konnyaku-nori (adhesive), 13,39 Kozo (Broussonetia Kazinoki) bush, 13 Kusaba, Major General Sueyoshi, 10, 11, 22 Kure Naval Base, Japan, 6 Lakehurst, Naval Air Station, New Jersey, 34 Launch sites, 16 Launching operations, 17, 63 Lemke, Representative William, 68 84 Lightening Project, 29 Majima, Dr. Masaichi, 11 Mausumata (Edgewortis Papyrifera) tree, 13n Matsumoti, Yusasa, 9 Meiji, Emperor, 21 Meteorology, 7 Mimura, General, 11 Mitchell, the Reverend Archie, 67 Mitchell, Mrs. Elsie, 67 Mitsubishi Saishi (paper factory), 11 Mt. Emily, Oregon, 6 Nakajima, Lieutenant Colonel Shozo, 37 Nakamura, Captain, 11 Nakamura, Tatsusuke, 10 Nakoso, Japan, 16, 17 (Figure 16) National Air and Space Museum, Smithsonian Institution, 34 Naval Airship Training and Experiment Command, 32 Navy balloon, 9 Nichigeki Music Hall, 13, 15 Niigata, Japan, 7, (Figure 6) Nippon Kakokin Company, 11 Nippon Paint Company, 39 Noborito Research Institute, 5n, 9, 11,13 Ogawa, Captain, 10 Ohara, Japan, 35 Oshima Island, 7, (Figure 6) Otsu, Japan, 16, 17, 63 Otsuki, Technical Major, 9 Patzke, Dick, 67 Patzke, Joan, 67 Radar, 32-34 Radiosonde, 9, 11, 24; plotting stations, 8 (Figure 6) Relief valve, 42 "Ro-Go Weapon," 3, 4 Ross, Dr. Clarence S., 34, 35 Sabishiro, Japan, 17 (Figure 16), 24 Sakhalin Island, 24 Saski, Dr. Tatsujiro, 11 Sendai, Japan, 7, 8 (Figure 6) Shimuzu, Rikuro, 37 Shinoda, Lieutenant General, 11 Shiogama, Japan, 17 (Figure 16), 35 Shio-no-Misaka, 7, 8 (Figure 6) Shoemaker, Sherman, 67 Showa Denko Company, 16, 38 Shrouds, 43 Sunset Project, 34, 35 (Figure 37), 36 Tada, Lieutenant General Reikichi, 3 Takada, Technical Major Teiji, 10,13 Takungpao (Chinese newspaper), 25 Tanaka, Technical Lieutenant Commander Kiyoshi, 10 Toho Theater, 15 Uchatius, Lieutenant, 3 Wajima, Japan, 7, 8 (Figure 6) Western Defense Command (United States), 29, 32, 34, 36 Weyerhaeuser Company, 68 Yagi, Dr. Hidetsugu, 11 Yonago, Japan, 7, 8 (Figure 6) AU.S. GOVERNMENT PRINTING OFFICE: 1973 O?469-627 85